[Federal Register Volume 67, Number 21 (Thursday, January 31, 2002)]
[Notices]
[Pages 4774-4775]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-1003]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Revisions to Advisory Circular--Flight Test Guide for 
Certification of Transport Category Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed advisory circular revision and request for 
comments.

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SUMMARY: This notice requests comments regarding proposed revisions to 
Advisory Circular (AC) 25-7A, ``Flight Test Guide for Certification of 
Transport Category Airplanes.'' This AC provides guidance on acceptable 
means, but not the only means, of demonstrating compliance with certain 
airworthiness standards for transport category airplanes. The proposed 
revisions to the AC complement proposed revisions to the airworthiness 
standards for transport category airplanes, published by separate 
document in the Federal Register on January 14, 2002 (67 FR 1846). This 
notice provides interested persons an opportunity to comment on the 
proposed revisions to the AC concurrently with the proposed rulemaking. 
Like all ACs, it is not mandatory, but is to provide guidance for 
applicants in demonstrating compliance with the objective safety 
standards set forth in the related rule.

DATES: Comments must be received by April 1, 2002.

ADDRESSES: Send all comments on the proposed AC revisions to the 
Federal Aviation Administration, Attention: Don Stimson, Airplane and 
Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Ave. SW., Renton, WA 98055-
4056. Comments may be examined at the above address between 7:30 a.m. 
and 4 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Susan Boylon, Program Management 
Branch, ANM-114, at the above address, telephone (425) 227-1152, or 
facsimile (425) 227-1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to comment on the proposed revisions 
to the AC by submitting such written data, views, or arguments, as they 
may desire. Commenters must identify the title of the AC and submit 
comments in duplicate to the address specified above. All comments 
received on or before the closing date for comments will be considered 
by the Transport Airplane Directorate before issuing the revised AC.

Discussion

    In a separate document published in the Federal Register on January 
14, 2002 (67 FR 1846), the FAA proposes to amend the airworthiness 
standards for transport category airplanes concerning miscellaneous 
flight requirements. We initiated the proposal under the ``Fast Track 
Harmonization Program'' November 26, 1999 (64 FR 66522). Adopting that 
proposal would eliminate regulatory differences between the 
airworthiness standards of the U.S. and the Joint Aviation Requirements 
of Europe, without affecting current industry design practices.
    In addition to the amendments proposed in Notice 02-01, the FAA 
also proposes to revise Advisory Circular (AC) 25-7A, ``Flight Test 
Guide for Certification of Transport Category Airplanes,'' to provide 
additional guidance concerning takeoff path, lateral control, trim 
(longitudinal), trim (airplanes with four or more engines), and 
demonstration of static longitudinal stability. This proposed revision 
to AC 25-7A should not be confused with other proposed revisions of AC 
25-7A on which the FAA is currently seeking comments. This revision 
only addresses guidance material associated with these specific 
airworthiness requirements. Issuance of a revised AC based on this 
proposal is contingent on adoption of the revisions to part 25 in 
Notice 02-01.

Proposed Revisions to AC 25-7A

    1. Add a new paragraph, 12a(1)(iii) to read as follows:
    (iii) The height references in Sec. 25.111 should be interpreted as 
geometrical heights.
    2. Revise paragraph 12e(2) to read as follows:
    (2) Procedures. The time between liftoff and the initiation of gear 
retraction during takeoff distance demonstrations should not be less 
than that necessary to establish an indicated positive rate of climb 
plus one second. For the purposes of flight manual expansion, the 
average demonstrated time delay between liftoff and initiation of gear 
retraction may be assumed; however, this value should not be less than 
3 seconds.
    3. Revise paragraph 22a(2) to read as follows:
    (2) Sections 25.147(c) and (e) require an airplane to be easily 
controllable with the critical engine(s) inoperative. Section 25.147(d) 
further requires that lateral control be sufficient to provide a roll 
rate necessary for safety, without excessive control forces or travel, 
at the speeds likely to be used with one engine inoperative. Compliance 
can normally be demonstrated in the takeoff configuration at 
V2 speed, because this condition is usually the most 
critical. Normal operation of a yaw stability augmentation system (SAS) 
should be considered in accordance with normal operating procedures. 
Roll response, Sec. 25.147(e), should be satisfactory for takeoff, 
approach, landing, and high speed configurations. Any permissible 
configuration that could affect roll response should be evaluated.
    4. Revise paragraph 22b as follows:
    b. Procedures. The following test procedures outline an acceptable 
means for demonstrating compliance with Sec. 25.147.
    5. Revise paragraph 22b(4) to read as follows:
    (4) Lateral Control--Roll Capability, Sec. 25.147(d).
    (i) Configuration:
    (A) Maximum takeoff weight.
    (B) Most aft c.g. position.
    (C) Wing flaps in the most critical takeoff position.
    (D) Landing gear retracted.
    (E) Yaw SAS on, and off, if applicable.
    (F) Operating engine(s) at maximum takeoff power.
    (G) The inoperative engine that would be most critical for 
controllability, with the propeller feathered, if applicable.
    (ii) Test Procedure: With the airplane in trim, or as nearly as 
possible in trim, for straight flight at V2, establish a 
steady 30 degree banked turn. It should be demonstrated that the 
airplane can be rolled to a 30 degree bank angle in the other direction 
in not more than 11 seconds. In this demonstration, the

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rudder may be used to the extent necessary to minimize sideslip. The 
demonstration should be made in the most adverse direction. The 
maneuver may be unchecked. Care should be taken to prevent excessive 
sideslip and bank angle during the recovery.
    6. Revise paragraph 22b(4) by renumbering it as paragraph 22b(5) as 
follows:
    (5) Lateral Control--Four or More Engines, Sec. 25.147(e).
    7. Revise paragraph 22b(5) by renumbering it as paragraph 22b(6) as 
follows:
    (6) Lateral Control--All Engines Operating, Sec. 25.147(f).

    Issued in Renton, Washington, on December 19, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-1003 Filed 1-30-02; 8:45 am]
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